Henry Percy, 1st Earl of Northumberland

Henry Percy, 1st Earl of Northumberland (10 November 1341-20 February 1408) was an English nobleman and the titular King of Mann. He was the father of Henry Percy, and the two of them rebelled against King Henry IV of England in 1403. Northumberland was slain at the Battle of Bramham Moor in 1408, ending his rebellion.

Biography
Henry Percy was born in Alnwick, Northumberland, England in 1341, and he was made Warden of the Marches toward Scotland in 1362. In 1367, he was entrusted with the supervision of all castles and fortified places in the Scottish marches. Due to his support for King Richard II of England, Richard made Percy and Earl and, briefly, Marshal of England. From 1383 to 1384, he served as Admiral of the Northern Seas. After Richard elevated his rival Ralph Neville to the position Earl of Westmorland in 1397, Percy supported the rebellion of Henry Bolingbroke, who became "King Henry IV". Henry IV appointed Percy as Constable of England, and he was sent to suppress Owain Glyndwr's rebellion. His efforts to make peace with Glyndwr were not appreciated, and the Percy family conspired against King Henry in 1403 as allies of Glyndwr. His son Henry Percy was slain at the Battle of Shrewsbury, and the rebellion was quelled. However, he supported Richard le Scrope's 1405 uprising, forcing him to flee to Scotland. In 1408, he invaded England in rebellion once more and was killed at the Battle of Bramham Moor; his severed head was subsequently displayed in London.